1. Field of the Invention
The present invention relates, in general, to a ball type cable tie having a release prevention tongue, and, more particularly, to a ball type cable tie having a release prevention tongue, wherein a release prevention tongue is formed on the upper portion of the fixed end of a strap which is coupled at the fixed end to a locking head, to doubly secure the locking head to the strap and to maintain the locking head in a reliably secured state, thereby decreasing a defective proportion of end products, and wherein a locking ball is guided in a rearward locking direction and pushed upward by elastic support action of the release prevention tongue which elastically operates, to prevent the locked state of the cable tie from being released and to maintain a tightly bundled state of the cable tie, thereby increasing the strength of the strap and improving the durability of the cable tie.
2. Description of the Prior Art
Generally, cable ties are widely used to bundle elongate objects such as electric wires of an electronic apparatus, cables of a ship, etc. Among such cable ties, a ball type cable tie is most widely used, in which a locking ball is moved forward and rearward to lock a strap. A ball type cable tie is disclosed in U.S. Pat. No. 4,399,592. This ball type cable tie has a structure in which the free end of a strap, having been threaded through a locking head, pushes a locking ball in a rearward locking direction, and a protrusion is formed to prevent the locking ball from being moved forward and the strap from thus becoming unlocked. However, in this type of cable tie, since the locking head and the fixed end of the strap are coupled to each other through the introduction of a latching finger projecting at an angle from the lower portion of the fixed end into a window defined in the bottom wall of the locking head, in the case that the latching finger is not bent or is bent below a predetermined height when manufacturing the strap, the locking head can be easily released from the strap, which inconveniences a user. Also, if the protrusion is crushed by the locking ball which is moved forward due to excessive load, the locked state of the strap is likely to be released.
In order to cope with these problems, a ball lock cable tie having a strap aperture is disclosed in U.S. Pat. No. 6,647,596. In this ball lock cable tie, an aperture is defined in the upper portion of the fixed end of a strap so that a locking ball can deform the threaded portion of the strap in the aperture to increase the locking strength of the cable tie. Nevertheless, even in this ball lock cable tie, since the locking head and the fixed end of the strap are coupled to each other through the introduction of a latching finger projecting at an angle from the lower portion of the fixed end into a window defined in the bottom wall of the locking head, in the case that the latching finger is not bent or is bent below a predetermined height when manufacturing the strap, it is difficult to prevent the release of the locking head from the strap. Further, because the aperture is defined in the strap, the strength of the strap itself is decreased, as a result of which the strap cannot stand substantial tensile force and is likely to break.